Sam Smith has made Lady Gaga cry with an emotional email he sent to the star.

After the 'Born This Way' singer read Smith's fan message, she took to Twitter to thank him, and described him as "so special" and "perfect". 

GAGA TWEETED: You're so special my baby. Your email made me cry @samsmithworld With the voice of an angel, u need no permission or advice. You're perfect.

Smith told the back story to the tweet, and explained why he decided to send Gaga a fan email.

"Someone had mentioned to me that Gaga knew of my stuff," he said. "I was just completely overwhelmed by that.

"I wrote her an email basically just saying, 'I remember being a 17-year-old, queuing up for your concert, dreaming up doing this and being in the music industry'.

"The thing I admire most about [her] was the hustle and what she did to get into the industry.

"I just ran with it, saying, 'Thank you so much for inspiring me to do this because the reason why I'm here now is partly because of you'," he continued, "and she seemed touched."

It was announced last week that Smith - along with Rixton, Ella Eyre and Gorgon - will be performing at Vevo's Halloween Party this year.

He also this month confirmed a UK tour for spring 2015.